Tuesday, 6 August 2013

Ehrenfest's Theorem

Similarly, the equation (known as Ehrenfest’s theorem), $gradV(\langle r \rangle) = m(d^2\langle r \rangle /dt^2)$, where V is the potential and r is the position operator, exhibits continuity between classical and quantum mechanics.

This formula is not quite correct. The expectation value brackets $\langle . \rangle$ are misplaced.